~eliasnaur/gio-example

1e576e23ff31394e41c41011a0025c1ca0381391 — Dan Kortschak 6 months ago 5fc7a08
galaxy: add simulation engine for galaxy example

This is essentially the code for the Gonum Barnes-Hut example code and
is donated to the Gio project.

Signed-off-by: Dan Kortschak <dan@kortschak.io>
3 files changed, 161 insertions(+), 0 deletions(-)

A galaxy/galaxy.go
M go.mod
M go.sum
A galaxy/galaxy.go => galaxy/galaxy.go +117 -0
@@ 0,0 1,117 @@
// SPDX-License-Identifier: Unlicense OR MIT

// The galaxy command is a seed for producing a demo
// for multiple objects moving in a Gio window.
package main

import (
	"log"
	"time"

	"golang.org/x/exp/rand"

	"gonum.org/v1/gonum/spatial/barneshut"
	"gonum.org/v1/gonum/spatial/r2"
	"gonum.org/v1/plot"
	"gonum.org/v1/plot/plotter"
	"gonum.org/v1/plot/plotutil"
	"gonum.org/v1/plot/vg"
)

type mass struct {
	d r2.Vec  // position
	v r2.Vec  // velocity
	m float64 // mass
}

func (m *mass) Coord2() r2.Vec { return m.d }
func (m *mass) Mass() float64  { return m.m }
func (m *mass) move(f r2.Vec) {
	// F = ma
	f.X /= m.m
	f.Y /= m.m
	m.v = m.v.Add(f)

	// Update position.
	m.d = m.d.Add(m.v)
}

func main() {
	rnd := rand.New(rand.NewSource(uint64(time.Now().Unix())))

	// Make 50 stars in random locations and velocities.
	stars := make([]*mass, 50)
	p := make([]barneshut.Particle2, len(stars))
	for i := range stars {
		s := &mass{
			d: r2.Vec{
				X: 100*rnd.Float64() - 50,
				Y: 100*rnd.Float64() - 50,
			},
			m: rnd.Float64(),
		}
		// Aim at the ground and miss.
		s.d = s.d.Scale(-1).Add(r2.Vec{
			X: 10 * rnd.NormFloat64(),
			Y: 10 * rnd.NormFloat64(),
		})

		stars[i] = s
		p[i] = s
	}
	vectors := make([]r2.Vec, len(stars))

	tracks := make([]plotter.XYs, len(stars))

	// Make a plane to calculate approximate forces
	plane := barneshut.Plane{Particles: p}

	// Run a simulation for 10000 updates.
	for i := 0; i < 10000; i++ {
		// Build the data structure. For small systems
		// this step may be omitted and ForceOn will
		// perform the naive quadratic calculation
		// without building the data structure.
		err := plane.Reset()
		if err != nil {
			log.Fatal(err)
		}

		// Calculate the force vectors using the theta
		// parameter.
		const theta = 0.1
		// and an imaginary gravitational constant.
		const G = 10
		for j, s := range stars {
			vectors[j] = plane.ForceOn(s, theta, barneshut.Gravity2).Scale(G)
		}

		// Update positions.
		for j, s := range stars {
			s.move(vectors[j])
			tracks[j] = append(tracks[j], plotter.XY{X: s.d.X, Y: s.d.Y})
		}
	}

	plt, err := plot.New()
	if err != nil {
		log.Fatalf("failed create plot: %v", err)
	}
	for i, t := range tracks {
		l, err := plotter.NewLine(t)
		if err != nil {
			log.Fatalf("failed create track: %v", err)
		}
		l.Color = plotutil.Color(i)
		l.Dashes = plotutil.Dashes(i)
		plt.Add(l)
	}
	plt.X.Min = -1000
	plt.X.Max = 1000
	plt.Y.Min = -1000
	plt.Y.Max = 1000
	err = plt.Save(20*vg.Centimeter, 20*vg.Centimeter, "galaxy.svg")
	if err != nil {
		log.Fatalf("failed to save file: %v", err)
	}
}

M go.mod => go.mod +2 -0
@@ 16,4 16,6 @@ require (
	golang.org/x/exp v0.0.0-20201210212021-a20c86df00b4
	golang.org/x/image v0.0.0-20201208152932-35266b937fa6
	golang.org/x/oauth2 v0.0.0-20190604053449-0f29369cfe45
	gonum.org/v1/gonum v0.8.2
	gonum.org/v1/plot v0.8.1
)

M go.sum => go.sum +42 -0
@@ 1,6 1,7 @@
cloud.google.com/go v0.34.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
dmitri.shuralyov.com/gpu/mtl v0.0.0-20190408044501-666a987793e9/go.mod h1:H6x//7gZCb22OMCxBHrMx7a5I7Hp++hsVxbQ4BYO7hU=
gioui.org v0.0.0-20200619180744-e2f3bbdfc367/go.mod h1:jiUwifN9cRl/zmco43aAqh0aV+s9GbhG13KcD+gEpkU=
gioui.org v0.0.0-20200628203458-851255f7a67b/go.mod h1:jiUwifN9cRl/zmco43aAqh0aV+s9GbhG13KcD+gEpkU=
gioui.org v0.0.0-20201206220452-acc3f704e478/go.mod h1:Y+uS7hHMvku1Q+ooaoq6fYD5B2LGoT8JtFgvmYmRzTw=
gioui.org v0.0.0-20201219144351-00c4a53036ad/go.mod h1:Y+uS7hHMvku1Q+ooaoq6fYD5B2LGoT8JtFgvmYmRzTw=
gioui.org v0.0.0-20201231162135-d23514fd5825 h1:k+PDfuxxrI4mNi9VrnVxOAGqg98zbKXazGh3X7Gk4Zg=


@@ 21,16 22,29 @@ git.wow.st/gmp/jni v0.0.0-20200619201040-d0d3f316ae09/go.mod h1:lfKZKu2afBKJODTF
git.wow.st/gmp/jni v0.0.0-20200827154156-014cd5c7c4c0 h1:Ynp3h+TC8k1clvf45D28VFQlmy0bPx8M/MG5bB24Vj8=
git.wow.st/gmp/jni v0.0.0-20200827154156-014cd5c7c4c0/go.mod h1:+axXBRUTIDlCeE73IKeD/os7LoEnTKdkp8/gQOFjqyo=
github.com/BurntSushi/xgb v0.0.0-20160522181843-27f122750802/go.mod h1:IVnqGOEym/WlBOVXweHU+Q+/VP0lqqI8lqeDx9IjBqo=
github.com/ajstarks/svgo v0.0.0-20180226025133-644b8db467af h1:wVe6/Ea46ZMeNkQjjBW6xcqyQA/j5e0D6GytH95g0gQ=
github.com/ajstarks/svgo v0.0.0-20180226025133-644b8db467af/go.mod h1:K08gAheRH3/J6wwsYMMT4xOr94bZjxIelGM0+d/wbFw=
github.com/boombuler/barcode v1.0.0/go.mod h1:paBWMcWSl3LHKBqUq+rly7CNSldXjb2rDl3JlRe0mD8=
github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/esiqveland/notify v0.9.1 h1:hX6ZD3FCQJXI46AzUM/iWekcMfnZ9TPE4uIu9Hrn1D4=
github.com/esiqveland/notify v0.9.1/go.mod h1:63UbVSaeJwF0LVJARHFuPgUAoM7o1BEvCZyknsuonBc=
github.com/fogleman/gg v1.2.1-0.20190220221249-0403632d5b90/go.mod h1:R/bRT+9gY/C5z7JzPU0zXsXHKM4/ayA+zqcVNZzPa1k=
github.com/fogleman/gg v1.3.0 h1:/7zJX8F6AaYQc57WQCyN9cAIz+4bCJGO9B+dyW29am8=
github.com/fogleman/gg v1.3.0/go.mod h1:R/bRT+9gY/C5z7JzPU0zXsXHKM4/ayA+zqcVNZzPa1k=
github.com/go-fonts/dejavu v0.1.0 h1:JSajPXURYqpr+Cu8U9bt8K+XcACIHWqWrvWCKyeFmVQ=
github.com/go-fonts/dejavu v0.1.0/go.mod h1:4Wt4I4OU2Nq9asgDCteaAaWZOV24E+0/Pwo0gppep4g=
github.com/go-gl/gl v0.0.0-20190320180904-bf2b1f2f34d7 h1:SCYMcCJ89LjRGwEa0tRluNRiMjZHalQZrVrvTbPh+qw=
github.com/go-gl/gl v0.0.0-20190320180904-bf2b1f2f34d7/go.mod h1:482civXOzJJCPzJ4ZOX/pwvXBWSnzD4OKMdH4ClKGbk=
github.com/go-gl/glfw v0.0.0-20190409004039-e6da0acd62b1 h1:QbL/5oDUmRBzO9/Z7Seo6zf912W/a6Sr4Eu0G/3Jho0=
github.com/go-gl/glfw v0.0.0-20190409004039-e6da0acd62b1/go.mod h1:vR7hzQXu2zJy9AVAgeJqvqgH9Q5CA+iKCZ2gyEVpxRU=
github.com/go-gl/glfw/v3.3/glfw v0.0.0-20200222043503-6f7a984d4dc4 h1:WtGNWLvXpe6ZudgnXrq0barxBImvnnJoMEhXAzcbM0I=
github.com/go-gl/glfw/v3.3/glfw v0.0.0-20200222043503-6f7a984d4dc4/go.mod h1:tQ2UAYgL5IevRw8kRxooKSPJfGvJ9fJQFa0TUsXzTg8=
github.com/go-latex/latex v0.0.0-20200518072620-0806b477ea35 h1:uroDDLmuCK5Pz5J/Ef5vCL6F0sJmAtZFTm0/cF027F4=
github.com/go-latex/latex v0.0.0-20200518072620-0806b477ea35/go.mod h1:PNI+CcWytn/2Z/9f1SGOOYn0eILruVyp0v2/iAs8asQ=
github.com/godbus/dbus/v5 v5.0.3 h1:ZqHaoEF7TBzh4jzPmqVhE/5A1z9of6orkAe5uHoAeME=
github.com/godbus/dbus/v5 v5.0.3/go.mod h1:xhWf0FNVPg57R7Z0UbKHbJfkEywrmjJnf7w5xrFpKfA=
github.com/golang/freetype v0.0.0-20170609003504-e2365dfdc4a0 h1:DACJavvAHhabrF08vX0COfcOBJRhZ8lUbR+ZWIs0Y5g=
github.com/golang/freetype v0.0.0-20170609003504-e2365dfdc4a0/go.mod h1:E/TSTwGwJL78qG/PmXZO1EjYhfJinVAhrmmHX6Z8B9k=
github.com/golang/protobuf v1.2.0 h1:P3YflyNX/ehuJFLhxviNdFxQPkGK5cDcApsge1SqnvM=
github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
github.com/google/go-github v17.0.0+incompatible h1:N0LgJ1j65A7kfXrZnUDaYCs/Sf4rEjNlfyDHW9dolSY=


@@ 39,18 53,33 @@ github.com/google/go-github/v24 v24.0.1 h1:KCt1LjMJEey1qvPXxa9SjaWxwTsCWSq6p2Ju5
github.com/google/go-github/v24 v24.0.1/go.mod h1:CRqaW1Uns1TCkP0wqTpxYyRxRjxwvKU/XSS44u6X74M=
github.com/google/go-querystring v1.0.0 h1:Xkwi/a1rcvNg1PPYe5vI8GbeBY/jrVuDX5ASuANWTrk=
github.com/google/go-querystring v1.0.0/go.mod h1:odCYkC5MyYFN7vkCjXpyrEuKhc/BUO6wN/zVPAxq5ck=
github.com/jung-kurt/gofpdf v1.0.0/go.mod h1:7Id9E/uU8ce6rXgefFLlgrJj/GYY22cpxn+r32jIOes=
github.com/jung-kurt/gofpdf v1.0.3-0.20190309125859-24315acbbda5/go.mod h1:7Id9E/uU8ce6rXgefFLlgrJj/GYY22cpxn+r32jIOes=
github.com/jung-kurt/gofpdf v1.16.2 h1:jgbatWHfRlPYiK85qgevsZTHviWXKwB1TTiKdz5PtRc=
github.com/jung-kurt/gofpdf v1.16.2/go.mod h1:1hl7y57EsiPAkLbOwzpzqgx1A30nQCk/YmFV8S2vmK0=
github.com/phpdave11/gofpdi v1.0.7/go.mod h1:vBmVV0Do6hSBHC8uKUQ71JGW+ZGQq74llk/7bXwjDoI=
github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
github.com/ruudk/golang-pdf417 v0.0.0-20181029194003-1af4ab5afa58/go.mod h1:6lfFZQK844Gfx8o5WFuvpxWRwnSoipWe/p622j1v06w=
github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
golang.org/x/crypto v0.0.0-20180820150726-614d502a4dac/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=
golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
golang.org/x/crypto v0.0.0-20190510104115-cbcb75029529/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
golang.org/x/exp v0.0.0-20180321215751-8460e604b9de/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
golang.org/x/exp v0.0.0-20180807140117-3d87b88a115f/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
golang.org/x/exp v0.0.0-20190125153040-c74c464bbbf2/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
golang.org/x/exp v0.0.0-20190306152737-a1d7652674e8/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
golang.org/x/exp v0.0.0-20191002040644-a1355ae1e2c3/go.mod h1:NOZ3BPKG0ec/BKJQgnvsSFpcKLM5xXVWnvZS97DWHgE=
golang.org/x/exp v0.0.0-20201008143054-e3b2a7f2fdc7/go.mod h1:1phAWC201xIgDyaFpmDeZkgf70Q4Pd/CNqfRtVPtxNw=
golang.org/x/exp v0.0.0-20201203231725-fa01524bc59d/go.mod h1:1phAWC201xIgDyaFpmDeZkgf70Q4Pd/CNqfRtVPtxNw=
golang.org/x/exp v0.0.0-20201210212021-a20c86df00b4 h1:c0f5UxfZlsfpBf1TXaGk9aMJGMWvPQBf9FdM8pAYZok=
golang.org/x/exp v0.0.0-20201210212021-a20c86df00b4/go.mod h1:1phAWC201xIgDyaFpmDeZkgf70Q4Pd/CNqfRtVPtxNw=
golang.org/x/image v0.0.0-20180708004352-c73c2afc3b81/go.mod h1:ux5Hcp/YLpHSI86hEcLt0YII63i6oz57MZXIpbrjZUs=
golang.org/x/image v0.0.0-20190227222117-0694c2d4d067/go.mod h1:kZ7UVZpmo3dzQBMxlp+ypCbDeSB+sBbTgSJuh5dn5js=
golang.org/x/image v0.0.0-20190802002840-cff245a6509b/go.mod h1:FeLwcggjj3mMvU+oOTbSwawSJRM1uh48EjtB4UJZlP0=
golang.org/x/image v0.0.0-20190910094157-69e4b8554b2a/go.mod h1:FeLwcggjj3mMvU+oOTbSwawSJRM1uh48EjtB4UJZlP0=
golang.org/x/image v0.0.0-20200430140353-33d19683fad8/go.mod h1:FeLwcggjj3mMvU+oOTbSwawSJRM1uh48EjtB4UJZlP0=
golang.org/x/image v0.0.0-20200618115811-c13761719519/go.mod h1:FeLwcggjj3mMvU+oOTbSwawSJRM1uh48EjtB4UJZlP0=
golang.org/x/image v0.0.0-20200927104501-e162460cd6b5/go.mod h1:FeLwcggjj3mMvU+oOTbSwawSJRM1uh48EjtB4UJZlP0=
golang.org/x/image v0.0.0-20201208152932-35266b937fa6 h1:nfeHNc1nAqecKCy2FCy4HY+soOOe5sDLJ/gZLbx6GYI=


@@ 85,12 114,25 @@ golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
golang.org/x/text v0.3.4 h1:0YWbFKbhXG/wIiuHDSKpS0Iy7FSA+u45VtBMfQcFTTc=
golang.org/x/text v0.3.4/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
golang.org/x/tools v0.0.0-20180525024113-a5b4c53f6e8b/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
golang.org/x/tools v0.0.0-20190206041539-40960b6deb8e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
golang.org/x/tools v0.0.0-20190927191325-030b2cf1153e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
golang.org/x/tools v0.0.0-20200207183749-b753a1ba74fa/go.mod h1:TB2adYChydJhpapKDTa4BR/hXlZSLoq2Wpct/0txZ28=
golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
gonum.org/v1/gonum v0.0.0-20180816165407-929014505bf4/go.mod h1:Y+Yx5eoAFn32cQvJDxZx5Dpnq+c3wtXuadVZAcxbbBo=
gonum.org/v1/gonum v0.8.1/go.mod h1:oe/vMfY3deqTw+1EZJhuvEW2iwGF1bW9wwu7XCu0+v0=
gonum.org/v1/gonum v0.8.2 h1:CCXrcPKiGGotvnN6jfUsKk4rRqm7q09/YbKb5xCEvtM=
gonum.org/v1/gonum v0.8.2/go.mod h1:oe/vMfY3deqTw+1EZJhuvEW2iwGF1bW9wwu7XCu0+v0=
gonum.org/v1/netlib v0.0.0-20190313105609-8cb42192e0e0 h1:OE9mWmgKkjJyEmDAAtGMPjXu+YNeGvK9VTSHY6+Qihc=
gonum.org/v1/netlib v0.0.0-20190313105609-8cb42192e0e0/go.mod h1:wa6Ws7BG/ESfp6dHfk7C6KdzKA7wR7u/rKwOGE66zvw=
gonum.org/v1/plot v0.0.0-20190515093506-e2840ee46a6b/go.mod h1:Wt8AAjI+ypCyYX3nZBvf6cAIx93T+c/OS2HFAYskSZc=
gonum.org/v1/plot v0.8.1 h1:1oWyfw7tIDDtKb+t+SbR9RFruMmNJlsKiZUolHdys2I=
gonum.org/v1/plot v0.8.1/go.mod h1:3GH8dTfoceRTELDnv+4HNwbvM/eMfdDUGHFG2bo3NeE=
google.golang.org/appengine v1.1.0/go.mod h1:EbEs0AVv82hx2wNQdGPgUI5lhzA/G0D9YwlJXL52JkM=
google.golang.org/appengine v1.4.0 h1:/wp5JvzpHIxhs/dumFmF7BXTf3Z+dd4uXta4kVyO508=
google.golang.org/appengine v1.4.0/go.mod h1:xpcJRLb0r/rnEns0DIKYYv+WjYCduHsrkT7/EB5XEv4=
rsc.io/pdf v0.1.1 h1:k1MczvYDUvJBe93bYd7wrZLLUEcLZAuF824/I4e5Xr4=
rsc.io/pdf v0.1.1/go.mod h1:n8OzWcQ6Sp37PL01nO98y4iUCRdTGarVfzxY20ICaU4=